1. Field of the Invention
The subject invention relates to apparatus and systems for mounting a hollow cylindrical member or any one of several hollow cylindrical members of different depths. By way of example, the subject invention more specifically relates to apparatus for mounting any one of several reels of different depths or widths for winding and storing magnetic recording tape or other web-like material.
2. Prior-Art Statement
There exist various proposals for releasably retaining a tubular member with the aid of a chuck as may, for instance, be seen from U.S. Pat. Nos. 2,647,701, 2,749,133, 2,903,200, 3,108,757, 3,239,159, 3,510,082, and 4,079,896.
As may be seen from some of these prior patents, it is also known to render expansible chucks slidable on a shaft to adjust their position to the widths of different roll cores and to equip such chucks with clamping devices for arresting their position on the particular shaft.
In practice, such approaches fail where reel hubs or other hollow cylindrical members have to be releasably retained at a high positional precision.
In this respect, the advanced reel hold-down of U.S. Pat. No. 3,233,841 has been widely used for years in the most demanding environments, including high-precision instrumentation tape recorders. In practice, different applications and tasks frequently require different tape widths which, in turn, require reels of different hub depths. In high-precision applications, it was thus necessary to provide a differently dimensioned reel hold-down structure for tape width.
The problems engendered by this prior-art approach were not confined to the necessity of having to provide different reel hold-down structures, but extended to the necessity of having to exchange reel hold-down structures on the magnetic tape transport for every tape width change. In fact, the most troublesome operation in changing a tape transport to a different tape width involved the mounting and adjustment of the reel hold-down structures or chucks because of the high precision required in positioning tape reels with respect to tape controlling components of the transport. This requirement became particularly burdensome in multi-track magnetic tape recording machines.
In this respect, there also exists a reel hold-down structure or chuck including a split-ring and a pair of tensioning members having meshing threads and being coupled to the split-ring for releasably retaining the reel with the split-ring. The split-ring and another member for defining a reference surface have flange portions for receiving the center of the wheel therebetween.
Again, the latter type of prior-art chuck was encumbered by the drawbacks mentioned above in connection with different tape widths according to the cited U.S. Pat. No. 3,233,841.